Clin Kidney J (2013) 6: 238–239 doi: 10.1093/ckj/sfs189 Advance Access publication 1 February 2013
Images in Nephrology
(Section Editor: G. H. Neild) Parapelvic cyst misdiagnosed as hydronephrosis Tsung-Liang Ma Division of Nephrology, Department of Internal Medicine, Chia-yi Christian Hospital, Chia-yi, Taiwan Correspondence and offprint requests to: Tsung-Liang Ma; E-mail: [email protected] Keywords: computed tomography; hydronephrosis; parapelvic cyst; ultrasonography
A 37-year-old male was referred to our hospital due to an abnormal ultrasound report of the right kidney in a regular health examination. The patient was asymptomatic and did not report fever, flank pain or dysuria. Repeated ultrasonography at our hospital revealed a hypoechoic area in the right central renal sinus,
Fig. 1. Renal ultrasonography revealed a hypoechoic area at central sinus region, suggesting hydronephrosis.
suggesting right hydronephrosis, but the obstructive site could not be found (Figure 1). Urinalysis revealed clear urine, and urine cytology was negative for malignant cells. For further evaluation of the obstructive site for the hydronephrosis, a computed tomography (CT) scan was arranged (Figure 2). It revealed a parapelvic cyst with mild displacement of the collecting system but no hydronephrosis was noted. As there were no symptoms, the patient was followed up without further treatment. Parapelvic cysts are uncommon and found in ∼1.25– 1.5% of autopsy cases [1]. Parapelvic cysts are usually solitary, originating from renal parenchyma and protruding into the sinus. Because of the hypoechoic character by ultrasonography and the special location in the renal sinus, parapelvic cysts are often misdiagnosed as hydronephrosis [2]. A large parapelvic cyst may sometimes compress the collecting system causing hydronephrosis, which needs surgical intervention [3]. Parapelvic cysts are rare and often benign and must be differentiated from hydronephrosis. The possibility of a parapelvic cyst must be kept in mind when the asymptomatic hydronephrosis is noted by ultrasonography with unknown causative obstructive lesion. Further image study such as CT scan is needed for the correct diagnosis.
Fig. 2. (A) Non-contrasted CT scan revealed a hypodense ovoid lesion in the right renal pelvis. (B) Excretory phase of contrasted CT revealed nonenhancement of the lesion. (C) CT urography (CTU) revealed mild displacement of the contrast-enhanced collecting system.
© The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For permissions, please email: [email protected].
Parapelvic cyst misdiagnosed as hydronephrosis Conflict of interest statement. None declared.
References 1. Tarzamni MK, Sobhani N, Nezami N et al. Bilateral parapelvic cysts that mimic hydronephrosis in two imaging modalities: a case report. Cases J 2008; 1: 161
239 2. Rha SE, Byun JY, Jung SE et al. The renal sinus: pathologic spectrum and multimodality imaging approach. Radiographics 2004; 24(Suppl 1): S117–S131 3. Kiryluk K, Gupta M. A large obstructive parapelvic cyst: challenging diagnosis and management. Kidney Int 2007; 71: 955 Received for publication: 16.12.12; Accepted in revised form: 30.12.12
Images in Nephrology
(Section Editor: G. H. Neild) Parapelvic cyst misdiagnosed as hydronephrosis Tsung-Liang Ma Division of Nephrology, Department of Internal Medicine, Chia-yi Christian Hospital, Chia-yi, Taiwan Correspondence and offprint requests to: Tsung-Liang Ma; E-mail: [email protected] Keywords: computed tomography; hydronephrosis; parapelvic cyst; ultrasonography
A 37-year-old male was referred to our hospital due to an abnormal ultrasound report of the right kidney in a regular health examination. The patient was asymptomatic and did not report fever, flank pain or dysuria. Repeated ultrasonography at our hospital revealed a hypoechoic area in the right central renal sinus,
Fig. 1. Renal ultrasonography revealed a hypoechoic area at central sinus region, suggesting hydronephrosis.
suggesting right hydronephrosis, but the obstructive site could not be found (Figure 1). Urinalysis revealed clear urine, and urine cytology was negative for malignant cells. For further evaluation of the obstructive site for the hydronephrosis, a computed tomography (CT) scan was arranged (Figure 2). It revealed a parapelvic cyst with mild displacement of the collecting system but no hydronephrosis was noted. As there were no symptoms, the patient was followed up without further treatment. Parapelvic cysts are uncommon and found in ∼1.25– 1.5% of autopsy cases [1]. Parapelvic cysts are usually solitary, originating from renal parenchyma and protruding into the sinus. Because of the hypoechoic character by ultrasonography and the special location in the renal sinus, parapelvic cysts are often misdiagnosed as hydronephrosis [2]. A large parapelvic cyst may sometimes compress the collecting system causing hydronephrosis, which needs surgical intervention [3]. Parapelvic cysts are rare and often benign and must be differentiated from hydronephrosis. The possibility of a parapelvic cyst must be kept in mind when the asymptomatic hydronephrosis is noted by ultrasonography with unknown causative obstructive lesion. Further image study such as CT scan is needed for the correct diagnosis.
Fig. 2. (A) Non-contrasted CT scan revealed a hypodense ovoid lesion in the right renal pelvis. (B) Excretory phase of contrasted CT revealed nonenhancement of the lesion. (C) CT urography (CTU) revealed mild displacement of the contrast-enhanced collecting system.
© The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For permissions, please email: [email protected].
Parapelvic cyst misdiagnosed as hydronephrosis Conflict of interest statement. None declared.
References 1. Tarzamni MK, Sobhani N, Nezami N et al. Bilateral parapelvic cysts that mimic hydronephrosis in two imaging modalities: a case report. Cases J 2008; 1: 161
239 2. Rha SE, Byun JY, Jung SE et al. The renal sinus: pathologic spectrum and multimodality imaging approach. Radiographics 2004; 24(Suppl 1): S117–S131 3. Kiryluk K, Gupta M. A large obstructive parapelvic cyst: challenging diagnosis and management. Kidney Int 2007; 71: 955 Received for publication: 16.12.12; Accepted in revised form: 30.12.12
